The present invention relates to elongated moldings to be installed in the roof of a vehicle, etc., as well as manufacturing methods and manufacturing devices for such elongated moldings.
As shown in FIG. 42, various types of long and narrow moldings (hereafter referred to as xe2x80x9celongated moldingsxe2x80x9d) are installed in a vehicle 50, such as an ordinary automobile, in order to fill gaps between components or for decorative purposes. For example, a so-called roof molding 60 is fitted and installed within the side grooves 52a formed along the edges of the roof (roof panel) 52 of the vehicle body 51. A window molding 55 is installed around the perimeter of the front window panel 53 in order to fill the gap between the window panel 53 and the window perimeter 53a formed along the vehicle body 51.
As shown in FIG. 45, the vehicle molding 60 (this figure shows a roof molding) typically consists of a plastic molded member 61, which constitutes the molding body 61a, and a metal core 66 which is embedded inside the molded member 61. Molding body 61a consists of a decorative area 62, which is exposed to the surface of the installation area to form the design surface 62a, and a mounting portion 65 to be installed in said installation area. Furthermore, the mounting portion 65 consists of a leg 63 to be inserted into the installation area (side grooves 52a of roof 52 in this case) and a securing portion 64 for securing the molding to said installation area. On the other hand, core 66 consists of a highly rigid metal, alloy, or hard resin material, whose cross section has typically been formed into a round wire shape, flat shape, or other different shapes such as a substantially U or L shape. Embedding such core 66 into molding body 61a improves the shape stability of molding 60 itself, thus improving the working efficiency of transportation and installation workers.
Such elongated molding 60 is usually manufactured by extruding an elastic molding material, such as a synthetic resin, elastomer, vulcanized rubber, etc., into a long and narrow shape. That is, as shown in FIG. 43, such elongated molding 60 can be manufactured using a manufacturing device (extrusion molding machine) equipped with an extrusion mold (die) 70 having a predetermined shape. In this figure, a molding material, such as a synthetic resin, is injected into extrusion mold 70 through supply tubes 72 and 74 that are connected to the mold 70. Then, the material is extruded through a predetermined extrusion port 73 in order to yield an elongated plastic molded member 61 (i.e., molding body) that has been extrusion-molded according to the shape of the extrusion port 73. Note that in this figure, a so-called two-color molding can be manufactured by supplying different molding materials from the two supply tubes 72 and 74.
Moreover, as shown in FIG. 43, by separately providing a core material introduction port 75 within the mold 70, a rigid core material 66 is introduced into the mold 70 along the longitudinal direction of molding body 61a that is extrusion-molded. In this way, an ordinary elongated molding 60 can be obtained with the core material 66 embedded inside the molded member 61 along the longitudinal direction.
However, accurately installing the aforementioned conventional molding in the predetermined installation area presents two problems that are described below.
The core material causes the first problem. That is, an elongated molding having the core material is embedded in the longitudinal direction presents the problems described below.
That is, molding body 61 that is conventionally extruded from extrusion port 73 has a linear shape as shown in FIG. 43. Because the core material 66 is embedded as was explained above, the rigidity of the core material 66 causes the molding to maintain a linear shape. Consequently, it is not easy to bend molding 60 to a desired configuration or angle, and it takes time to fit molding 60 into the shape of an installation area having complicated contours, such as roof side grooves 52a and the window perimeter 53a of vehicle 50 shown in FIG. 42.
Furthermore, roof 52 and body 51 of vehicle 50 have unique curved surfaces depending on the model and therefore, roof molding 60, etc. must also be bent (including twisting and flexing. Hereafter, xe2x80x9cbendingxe2x80x9d shall mean such a process.) to conform to those curved surfaces for installation. However, it has been difficult to bend conventional roof moldings 60, in which a highly rigid core material is embedded, to conform accurately to the shape of the roof 52, etc. A typical example is shown in FIG. 44. Note that this figure shows a cross-section of the roof molding 60 along the portion that is inserted into side grooves 52a. 
As shown in FIG. 44, for a conventional long roof molding 60 in which the core material 66 is embedded, it has been difficult to install the molding 60 such that it accurately matches the bending direction (traveling line) of roof side grooves 52a. That is, because it is not easy to bend roof molding 60 in the desired direction in different spots in order to match the contour of roof side grooves 52a, problems have occurred in some cases in which molding 60 becomes offset with respect to the outer wall 52b of side grooves 52a in some areas while it becomes offset with respect to the inner wall 52c of side grooves 52a in other areas. This kind of poor match between the formation direction (traveling line) of the molding installation area (e.g., roof side grooves 52a) and the bending direction (traveling line) of the molding, i.e., a traveling line mismatch, detracts from the appearance and thus is not desirable in terms of product value.
The second problem is caused by the configuration of the molding body. That is, in recent years, the need for improved vehicle designs has resulted in requirements for improved decorative characteristics and the appearance of the elongated molding that is installed on the exterior surfaces of vehicles. Consequently, as shown in FIG. 45, a molded member having a different composition from the molded member, which comprises the interior of decorative area 62 or mounting portion 65, is typically utilized for design surface 62a of decorative area 62 in order to achieve improved scratch resistance and luster. For example, in the case of roof molding 60 consisting of TPO (a thermoplastic elastomer from the polyolefin family), the design surface 62a is formed using a TPO that contains a large proportion of hard PP (polypropylene), whereas other areas are formed using a soft TPO that contains relatively less PP in order to achieve improved installation characteristics.
However, in a molding that consists of two or more kinds of molded members having different compositions as described above, the different compositions usually result in different mold shrinkage rates among the different molded members, resulting in the problem described below.
That is, as schematically shown in FIG. 46, if molding 80 is formed by laminating molded member 81, which has a relatively large molding shrinkage rate, and molded member 82, which has a relatively small molding shrinkage rate in the longitudinal direction, a linear shape can be maintained immediately following extrusion as shown on the top area in FIG. 46. However, after extrusion (typically during the cooling process), the different mold shrinkage rates of the two molded members 81 and 82 cause an unintended curvage (warpage) in molding 80 toward the member having the larger molding shrinkage rate.
When such an unintended curvage occurs, it becomes difficult to install the molding accurately in conformance with the contour (including surface configurations that are partially or entirely flat as well. Hereafter, xe2x80x9ccontourxe2x80x9d shall mean such a surface configuration.) of the installation areas in the vehicle roof 52, etc. The external appearance of the installation areas is also spoiled, which is not desirable in terms of product value.
Therefore, the objective of the present invention is to provide elongated moldings that solve the aforementioned first and/or second problems and that has property of accurately conforming to the shapes of installation areas having complicated contours (hereafter referred to as xe2x80x9cshape conformancexe2x80x9d). That is, several of the inventions disclosed herein have been created to solve the aforementioned conventional problems relating to the shape conformance of the elongated molding to be installed/used in vehicle roofs, etc., and to provide moldings that can be easily curved or bent in the desired angle or orientation, a manufacturing method for easily manufacturing such molding, and a manufacturing device for that purpose.
Several of the inventions disclosed herein have been created to solve the aforementioned conventional problems relating to elongated moldings consisting of two or more kinds of molded members having different compositions, and to provide elongated molding that, despite being comprised of two or more molding members having different mold shrinkage rates, prevents the occurrence of an unintended curvature and that can be installed accurately in conformance to the installation areas, and a manufacturing method thereof.
The moldings of the present invention that achieve the aforementioned objective are moldings that have been formed into an elongated shape and the molding body is formed by joining two or more plastic molded members having mutually different mold shrinkage rates in at least some portions along the longitudinal direction. Furthermore, in at least some portions of the molding body consisting of said two or more plastic molded members, two or more curved areas having mutually different curvatures contact each other along the longitudinal direction. Moreover, the cross-sectional configuration of the two or more plastic molded members, which can be seen in the cross section of the molding body, varies between two adjacent curved areas among said two or more curved areas.
Note that in this Specification, xe2x80x9cconfiguration within the cross sectionxe2x80x9d means the pattern formed by the two or more plastic molded members (cross sections), which can be seen in the cross section relative to the longitudinal direction of the molding body. Therefore, the fact that the configuration within the cross section differs between two different cross sections of the molding body means that the patterns formed from the two or more plastic molded members (cross sections) (typically the positions and modes of the cross sections of individual plastic molded members) are mutually different.
Also, in this Specification, xe2x80x9cmolding shrinkage ratexe2x80x9d refers to the degree of shrinkage that occurs in the plastic molded member after said molded member is molded (typically extrusion molding). xe2x80x9cCurved areaxe2x80x9d is a term that refers to a part in the longitudinal direction, having any curvature, and is not restricted to one having a particular curvature. Therefore, a part that is substantially linear in the longitudinal direction and whose curvature is approximately 0, for example, is also included in the curved area described in this Specification.
In the molding of the present invention having such a configuration, curved areas having the different curvatures can be formed adjacent to each other by making the configuration within the cross section differ along the longitudinal direction of the molding body. In other words, in the molding of the present invention, curved areas having different curvatures can be formed in different areas of the molding body by intentionally varying the configuration within the cross section among different areas along the longitudinal direction of the molding body. This is because varying the configuration within the cross section can create different mold shrinkage rates at different areas along the longitudinal direction of the molding body accordingly since plastic molded members having different mold shrinkage rates are formed together into the molding body.
Therefore, according to the molding of the present invention, the bending direction and curvature of the molding itself can be varied (adjusted) for different areas in the longitudinal direction of the molding in correspondence to said mold shrinkage rates. Consequently, according to the molding of the present invention, despite the fact that multiple plastic molded members having mutually different mold shrinkage rates form the molding body, curvatures conforming to the shapes (contours) of the installation areas can be intentionally generated while preventing the generation of undesirable curvatures, thus realizing installation that accurately conforms to said installation areas.
One of the preferred embodiments of the molding of the present invention, in which the configuration within the cross section is varied between the aforementioned two adjacent curved areas (hereafter referred to as xe2x80x9cthe first molding of the present inventionxe2x80x9d) has one plastic molded member comprising the molding body and another or two or more plastic molded members having mold shrinkage rates that are different from that of said first plastic molded member and that are embedded along the longitudinal direction of said first plastic molded member, wherein in at least parts of the molding body, the embedding positions of said other plastic molded members are varied such that the relative positions of the plastic molded members within the cross section of the molding body differ between the two adjacent curved areas.
Note that in this Specification, xe2x80x9cthe relative position within the cross section of the molding bodyxe2x80x9d of the other plastic molded member refers to the positional relationship between the location of the cross section of the other plastic molded member existing within the cross section of the targeted molding body and a specific location in the cross section of the targeted molding body (one location on the perimeter of the cross section is typically chosen), as viewed from said specific location. Therefore, a statement that such a relative position varies along the longitudinal direction of the molding body, i.e., between the two adjacent curved areas, typically means that the position, where the cross-sectional shape of the other plastic molded member exists, varies sufficiently to be clearly recognizable between individual cross sections along the longitudinal direction of the molding body (i.e., the aforementioned two adjacent curved areas), as viewed from one specific location on the perimeter of the installation area (typically the leg area to be described below) of the molding body or on the decorative surface of the molding body.
In the first molding of the present invention having such a configuration, the embedded position of the other plastic molded member, as viewed from the cross section of the molding body, varies between predetermined areas along the longitudinal direction of the molding. That is, the offset state of the other plastic molded member, which is to be embedded along the longitudinal direction, within the cross section varies between said areas.
Additionally, in the first molding of the present invention, the aforementioned other plastic molded member is typically comprised of a molding material that is different from the molding material used for forming the first plastic molded member. Consequently, in the first molding of the present invention, curves or bends having different curvatures can be realized for individual areas of the molding body in correspondence to the offset status of said other plastic molded member. That is, the first and the other plastic molded members consisting of mutually different materials are formed together into the molding body, and as a result, a difference in shrinkage rates can be created based upon a difference in materials between the first plastic molded member and the other plastic molded member after the molding body is formed (cooling). During this step, varying the embedded location of the other plastic molded member within the cross section of the molding body for different areas along the longitudinal direction can vary (adjust) the bending direction of the molding body itself for each of said areas in correspondence to the difference in said shrinkage rates.
Therefore, according to the first molding of the present invention, a bending process that conforms to the shape of the installation area (contour) can be easily performed and installation that accurately conforms to said installation area can be realized.
In one of the preferred forms of the first molding of the present invention, the other plastic molded member consists of a molded member that is harder than the first plastic molded member. Molding having such a configuration can achieve a high level of shape stability equaling a conventional molding having a metal core.
In another preferred form of the first molding of the present invention, the other plastic molded member consists of a molded member that has a larger molding shrinkage rate than the first plastic molded member. A molding having such a configuration allows the molding body to be easily curved or bent in the direction in which the other plastic molded member formed from a material having said larger molding shrinkage rate is offset.
An especially preferred form of the first molding of the present invention is one in which at least some parts of the molding body in the longitudinal direction are curved or bent in the direction in which the other plastic molded member is offset, as viewed from the cross section of the molding body. Such non-linear molding can achieve a high degree of shape conformance to the contour of the installation area.
Still another preferred form of the molding of the present invention (hereafter referred to as xe2x80x9cthe second molding of the present inventionxe2x80x9d), in which the configuration within the cross section is varied between the two adjacent curved areas, is characterized in that the locations of the two or more plastic molded members and/or their area proportions on the cross section of the molding body vary between the two adjacent curved areas.
In the second molding of the present invention having such a configuration, a form in which the curved areas having different curvatures are adjacent to each other can be realized by varying the locations and/or area proportions of the two or more plastic molded members having mutually different mold shrinkage rates, as viewed from the cross section of the molding body, along the longitudinal direction.
That is, the second molding of the present invention realizes the formation of curved areas having different curvatures in individual areas of the molding body by intentionally varying the locations and/or area proportions. This is because plastic molded members having individually different mold shrinkage rates are formed together into the molding body, and as a result, differences in mold shrinkage rates can be created for individual areas, as viewed from the cross section of the molding body, in correspondence to the locations and area proportions of individual plastic molded members after the molding body is formed (cooling). Moreover, by varying the locations and/or area proportions of such multiple plastic molded members for individual positions along the longitudinal direction, the bending direction and curvature of the molding itself can be varied (adjusted) for individual positions in correspondence to the differences in said mold shrinkage rates.
Therefore, according to the second molding of the present invention, despite the fact that the molding body consists of a plurality of plastic molded members having mutually different mold shrinkage rates, curvatures conforming to the shapes (contours) of the installation areas can be intentionally generated while preventing the generation of undesirable curvatures, thus realizing installation that accurately conforms to said installation areas.
In one embodiment of the second molding of the present invention, the molding body is configured by joining the two or more plastic molded members in the longitudinal direction over its entire length. According to such a molding, it is possible to intentionally generate curvatures conforming to the shapes (contours) of the installation areas over the entire longitudinal direction.
In another embodiment of the second molding of the present invention, at least one of the curved areas forms a linear molded part that maintains a substantially linear shape in the longitudinal direction. According to such a molding, it is possible to realize an installation that accurately conforms to the installation area even if some parts of the installation area have flat shapes (contours).
In one of the preferred forms of the second molding of the present invention, between at least one pair of adjacent curved areas among the curved areas, one of the two or more plastic molded members comprising said curved areas is distributed and positioned in two or more locations that are separated from each other within the cross section of the molding body, wherein the area proportion of said one plastic molded member in at least one location of said two or more locations, within the cross section of the molding body, is different between said two curved areas.
In the second molding of the present invention having such a characteristic, by varying the area proportion (i.e., the position and mass proportion) of the one plastic molded member, which is distributed and positioned in two or more locations, along the longitudinal direction, two or more curved areas having mutually different curvatures can be easily formed adjacent to each other in the longitudinal direction.
In another preferred form of the second molding of the present invention, between at least one pair of adjacent curved areas among the curved areas, the area proportions of at least two of the two or more plastic molded members comprising said curved areas, within the cross section of the molding body, are substantially the same between said two curved areas, and the locations of said at least two plastic molded members within the cross section of the molding body are different from each other between said two curved areas.
In the second molding of the present invention having such a characteristic, by varying the locations (i.e., positions) of the two or more plastic molded member having mutually different values for the mold shrinkage rates along the longitudinal direction, two or more curved areas having mutually different curvatures can be easily formed adjacent to each other in the longitudinal direction.
In still another preferred form of the second molding of the present invention, between at least one pair of adjacent curved areas among the curved areas, two or more plastic molded members comprising said curved areas contain a first plastic molded member having a relatively large molding shrinkage rate and a second plastic molded member having a relatively small molding shrinkage rate, wherein the locations of said first and second plastic molded members within the cross section of the molding body in said two curved areas are offset by 180 degrees from each other between said two curved areas, as viewed from said cross section (i.e., said first and second plastic molded members are rotated from each other by approximately 180 degrees across the two curved areas, using the longitudinal direction of one of the curved areas as the rotation axis).
In the molding having such a characteristic, first and second molded members having the mutually different mold shrinkage rates are alternately positioned between two curved areas that are adjacent in the longitudinal direction. That is, the locations of these two plastic molded members within the cross section of the molding body are different from each other between the two curved areas in the transverse direction (i.e., the right-left direction, up-down direction, and other direction perpendicular to the longitudinal direction. Hereafter, xe2x80x9ctransverse directionxe2x80x9d shall mean such directions.). Consequently, it is possible to alternate the bending direction in one curved area and the bending direction in the other curved area in the transverse direction (typically in an approximate S shape). Therefore, according to the molding in the present format, it is possible to realize L installation that accurately conforms to an installation area that is curved in an S shape in the left-right or top-down direction.
Furthermore, the present invention provides molding in another configuration that can achieve the aforementioned objective (hereafter referred to as xe2x80x9cthe third molding of the present inventionxe2x80x9d). That is, the third molding of the present invention is molding that is formed in a long shape, and its molding body is formed by joining two or more plastic molded members having mutually different mold shrinkage rates in at least some parts in the longitudinal direction. Furthermore, a linearly molded area that substantially maintains a linear shape in the longitudinal direction is formed in at least some parts of the molding body comprised of said two or more plastic molded members, wherein one or more of the two or more plastic molded members are distributed and positioned in two or more locations that are separated from each other within the cross section of the molding body in said linearly molded area such that the molding shrinkage rate in said linearly molded area in the longitudinal direction is nearly uniform over the entire cross section of the molding body.
The third molding of the present invention having such a configuration can maintain linearity after molding while preventing the aforementioned unintended curvage (warpage) shown in FIG. 46, in the linearly molded area. That is, the molding body is formed by integrating together plastic molded members having different mold shrinkage rates, and as a result, the molding shrinkage rate differs in each area within the cross section of the molding body in correspondence to the location and area proportion of each plastic molded member. In this process, the third molding of the present invention specifies the locations and area proportions of the individual plastic molded members such that the molding shrinkage effects of individual plastic molded members in the linearly molded area can counteract each other as a whole, i.e., so that a bias in molding shrinkage is not created that would bend the molding body in one particular direction.
Therefore, according to the molding having the present configuration, despite the fact that at least part of the molding body is comprised of plural plastic molded members having mutually different mold shrinkage rates, linearity can be substantially maintained in the longitudinal direction in said area. Therefore, installation that accurately conforms to an installation area having a flat surface can be realized.
A preferred form of the molding of the present invention is formed from synthetic resin materials that have mutual compatibility and can be fused together during the molding of the two or more plastic molded members comprising the molding body. According to such a configuration, strong bonding between molded members can be achieved even after mold shrinkage has occurred.
A preferred form of the molding of the present invention (including the aforementioned first, second, and third molding of the present invention) is formed as roof molding to be installed in the installation area formed on the roof of a vehicle, and in which curves or bends have been formed in correspondence to the contour of said installation area.
Molding having such a configuration can realize shape conformance, i.e., conformance to the contour unique to a vehicle, and can be installed while accurately conforming to the roof shape (contour) of the vehicle.
As another aspect of achieving the aforementioned objective, the present invention provides a method of manufacturing the first molding of the present invention.
That is, the molding manufacturing method of the present invention (hereafter referred to as xe2x80x9cthe first molding manufacturing method of the present inventionxe2x80x9d) is a method of manufacturing elongated molding that has a plastic molded member comprising the molding body and another or two or more plastic molded members embedded along the longitudinal direction of said first plastic molded member, and includes (a) a process for supplying to the interior of an extrusion mold, a molding material for forming the plastic molded member comprising the molding body and a molding material that is different from said first molding material and that comprises another plastic molded member embedded inside said first plastic molded member, and (b) a process for extruding from the extrusion port of said extrusion mold, a molding body in which said other molding material is embedded in the longitudinal direction. Moreover, an operation for varying the embedded position of said another molding material and/or an operation for moving the position of said extrusion port are included such that the relative position of the other molding material within the cross section of the molding body varies along the longitudinal direction at predetermined timing.
According to the molding manufacturing method of the present invention having such a configuration, the embedding position of the other molding material (i.e., the other plastic molded member) to be embedded in the molding body can be offset in mutually different orientations between different parts along the longitudinal direction. Consequently, the first molding manufacturing method of the present invention can ideally manufacture the first molding of the present invention having the aforementioned various characteristics.
A preferred embodiment of the first molding manufacturing method of the present invention is a method in which the operation for varying the embedding position of the aforementioned other molding material and/or the aforementioned operation for moving the extrusion port are performed multiple times at different timings during the extrusion molding of a single piece of elongated molding body.
With such a manufacturing method, the embedding position of the other molding material (the other plastic molded member) to be embedded in the molding body can be offset as desired for each part along the longitudinal direction. According to the manufacturing method in this embodiment, molding can be manufactured in which a curve or bend having a different curvature (radius of curvature) according to the offset state is formed for each part of the molding body in the longitudinal direction. Consequently, this method can provide the molding of the present invention, which has superior shape conformance to the contours of the installation areas of a vehicle, etc., where the molding is to be installed.
As another aspect of achieving the aforementioned objective, the present invention provides a device for manufacturing the first molding of the present invention.
The molding manufacturing device of the present invention is a device for manufacturing elongated molding, and is provided with an extrusion mold having an extrusion port for extruding a molding material supplied from outside with a predetermined cross-sectional shape; and the extrusion mold is provided with a molding material supply area for supplying a molding material, which is used for forming the plastic molded member comprising the molding body, into said mold and with another or two or more molding material supply areas for supplying the other molding material(s), which is to be embedded in said first plastic molded member, into said mold. Moreover, the extrusion mold is configured to extrude from the extrusion port, the molding body in which the other molding material supplied from the other molding material supply area is introduced into and embedded in the first molding material supplied from the first molding material supply area. Furthermore, an embedding position varying means for varying the embedding position of said other molding material is provided such that the relative position of the other molding material to be extruded from the extrusion port, within the cross section of the molding body, can be varied along the longitudinal direction.
The molding manufacturing device of the present invention having such a configuration can be used for ideally implementing the first molding manufacturing method of the present invention. That is, the first molding material comprising the first plastic molded member and the other molding material comprising the other plastic molded member can be individually and separately supplied to the extrusion mold for the molding. Then, the molding body, in which the other molding material supplied into the mold is embedded in the first molding material, can be extruded from the extrusion port. In this way, it becomes possible to manufacture elongated molding that has the another or two or more plastic molded members embedded in the first plastic molded member comprising the molding body.
During this step, because the embedding position varying means is provided, the molding manufacturing device of the present invention can vary and offset along the longitudinal direction, the embedding positions of the other molding material (the other plastic molded member) to be embedded in the molding body, which is to be extruded from the extrusion port. Therefore, the molding manufacturing device of the present invention can ideally manufacture the first molding of the present invention having the aforementioned various characteristics.
In one of the preferred embodiments of the molding manufacturing device of the present invention, the extrusion mold is provided with another molding material introduction port for introducing the other molding material while it is embedded in the first molding material supplied into the mold from the first molding material supply area. Moreover, said extrusion mold and the other molding material introduction port are installed such that the position of the face of said other molding material introduction port can be varied relative to the extrusion port.
With such a configuration, the embedding position of the aforementioned other molding material can be varied by varying the aforementioned position of the face.
A more preferred molding manufacturing device of the present invention is a manufacturing device that is configured to change the aforementioned position of the face reversibly and continuously.
With such a manufacturing device, the embedding positions of the other or two or more molding materials (the other or two or more plastic molded members) to be embedded in the molding body can be offset as desired for each part along the longitudinal direction. Therefore, the manufacturing device in this embodiment can ideally manufacture the molding of the present invention, which has superior shape conformance to the contours of the installation areas of a vehicle, etc., where the molding is to be installed.
As another aspect of achieving the aforementioned objective, the present invention provides a method of preferably manufacturing the second molding of the present invention.
That is, such a molding manufacturing method of the present invention (hereafter referred to as xe2x80x9cthe second molding manufacturing method of the present inventionxe2x80x9d) is a method of manufacturing elongated molding in which two or more curved areas having mutually different curvatures can be formed adjacent to each other in the longitudinal direction after extrusion molding, and includes (a) a step of supplying to the extrusion mold, two or more plastic molded member molding materials whose post-molding mold shrinkage rates are different from each other, and (b) a step of extruding from the extrusion port of said extrusion mold, a molding body formed by joining said two or more plastic molded member molding materials, wherein, during the execution of processes (a) and (b), an operation for varying the locations and/or area proportions of the two or more plastic molded member molding materials within the cross section of the molding body to be extruded from the extrusion port is performed once or two or more times such that two or more curved areas having mutually different curvatures are formed adjacent to each other in the formed molding body in the longitudinal direction.
According to the molding manufacturing method of the present invention having such a characteristic, the varying operation during extrusion molding can mutually vary the locations and/or area proportions of the two or more plastic molded members comprising the molding body, as viewed from the cross section of the molding body, in different parts along the longitudinal direction. During this step, curved areas having the desired orientations and curvatures are formed by varying the locations and/or area proportions such that the mold shrinkage rate of the molding body varies along the transverse direction. This is because the extruded molding body is bent in the direction of the larger mold shrinkage rate according to the difference in said mold shrinkage rates.
Consequently, the molding manufacturing method of the present invention having such a configuration can preferably manufacture the molding of the present invention.
In one of the preferred embodiments of the second molding manufacturing method of the present invention, one of the plastic molded member molding materials to be supplied to the mold is supplied to said mold so as to be distributed and positioned in two or more mutually separate locations within the cross section of the molding body, wherein at least one of the aforementioned one or two or more varying operations is an operation for varying the area proportion of said first plastic molded member molding material within the cross section of the molding body in at least one of said two or more locations before and after said varying operation.
According to a molding manufacturing method having such a characteristic, by varying the area proportion (i.e., location and mass proportion) of the first plastic molded member molding material that is distributed and positioned in the two or more locations along the longitudinal direction, a molding whose bending direction and/or curvature varies along the longitudinal direction can be preferably manufactured.
In one of the preferred embodiments of the second molding manufacturing method of the present invention, at least one of the aforementioned one or two or more varying operations is an operation for alternately positioning different plastic molded member molding materials of said two or more plastic molded member molding materials after said varying operation, in the locations where the two or more plastic molded member molding materials were positioned within the cross section of the molding body before the varying operation.
A molding manufacturing method having such a characteristic can preferably manufacture a molding in which its bending direction and/or curvature varies along the longitudinal direction, by alternating the locations of the two or more plastic molded members having the aforementioned different mold shrinkage rates for each curved area.
In another preferred embodiment of the second molding manufacturing method of the present invention, the plastic molded member molding materials to be supplied to the mold include a first plastic molded member molding material having a relatively large post-molding mold shrinkage rate and a second plastic molded member molding material having a relatively small post-molding mold shrinkage rate, wherein at least one of the aforementioned one or two or more varying operations is an operation for rotating the locations of said two plastic molded member molding materials within the cross section of the molding body by approximately 180 degrees in relative terms as viewed from said cross section.
A molding manufacturing method having such a characteristic can preferably manufacture the molding in which the bending direction in one of adjacent curved areas and the bending direction in the other curved area are alternated in the transverse direction (typically in an approximate S shape).
In a particularly preferred embodiment of the second molding manufacturing method of the present invention, the change in the area proportion by the varying operation is achieved by adjusting (varying as needed) the flow rates of the two or more plastic molded member molding materials to be supplied to the extrusion mold (die). That is, when the flow rate (i.e., the supply volume per unit time) of each plastic molded member molding material is varied, the area proportion of each molding material within the cross section of the molding body to be extruded varies in response.
In another particularly preferred embodiment of the second molding manufacturing method of the present invention, the change in the location during the varying operation is achieved by switching the channels for the two or more plastic molded member molding materials inside said extrusion mold by moving part of the extrusion mold. By using such a movable-type extrusion mold, the location swapping can be smoothly performed.
Another molding manufacturing method of the present invention for achieving the aforementioned objective (hereafter referred to as xe2x80x9cthe third molding manufacturing method of the present inventionxe2x80x9d) includes (a) a step of supplying to an extrusion mold, two or more plastic molded member molding materials having mutually different post-molding mold shrinkage rates, and (b) a step of extruding from the extrusion port of said extrusion mold, a molding body formed by joining said two or more plastic molded member molding materials, wherein steps (a) and (b) are performed such that one or more of the aforementioned two or more plastic molded member molding materials are distributed and positioned in two or more locations that are separated from each other within the cross section of the molding body, to make the molding shrinkage rate in the longitudinal direction of the molding body after molding over the entire cross section of the molding body nearly uniform at least part of the time.
The third molding manufacturing method of the present invention having such a configuration can preferably manufacture the third molding of the present invention, in which a linear molded area that maintains a substantially linear shape in the longitudinal direction in at least some area in the longitudinal direction after extrusion molding is formed.
As explained above, the present invention can provide a molding in which partial curves or bends having different curvatures can be easily achieved and a manufacturing method thereof. With this molding, curves or bends having different curvatures can be easily obtained for each area along the longitudinal direction, and as a result, the molding can be easily installed in conformance to the installation areas having complicated contours, such as the perimeters of window panels and roof-side grooves of a vehicle.
Furthermore, the present invention can provide an elongated molding that can be installed in excellent conformance to the shape of the installation area and a manufacturing method thereof, while preventing the generation of unintended curves despite the fact that the elongated molding consists of two or more molded members having different mold shrinkage rates. With this molding, curved areas having different curvatures can be easily formed adjacent to each other in the longitudinal direction based upon the post-molding shrinkage effects, and as a result, the molding can be easily installed in conformance to the installation areas having complicated contours, such as the perimeters of window panels and roof-side grooves of a vehicle.
Moreover, these types of molding of the present invention can realize an installation that accurately conforms to the shape of the predetermined installation area, and as a result, can improve the appearance of the installation state and can dramatically increase the product value of vehicle molding, etc.